Editorial Blog of the Month
Leg muscles are the muscles of life; They allow us to get up, move around and do daily activities. They also play an important role in maintaining health; skeletal muscles are some of the largest stores of protein, the ingredient that we need to rebuild cells, fight disease, and play an important role in the prevention and management of chronic diseases.
I often get asked what muscles are the most important to train and the answer is always easy, legs. Here are some of the reasons why.
The role of skeletal muscles
Skeletal muscles are the largest organ in the body, making up ~ 40-45% of body mass. Research has shown that these muscles have a direct liaison to many functions beyond locomotion, such as metabolic rate, glucose metabolism, cognition, blood pressure, and blood lipid levels. Therefore, muscle mass and strength has been directly linked to the treatment and prevention of many diseases.
Without appropriate usage muscle mass decreases with the average person losing around 30-40% of their muscle mass between the age of 20 to 80 years. After the age of 40, the amount of muscle tissue decreases by 8% per decade, and after 70 years it accelerates to 15% per decade.
This loss of muscle mass, Sarcopenia, is associated with impaired health and functional performance, leading to an increased risk of falls, osteoporosis, fragility, fractures, frailty, loss in independence, reduced quality of life and premature mortality.
Strategies to prevent muscle loss must be implemented early. Special attention must be paid to people who are immobilized due to injury or illness, especially older people who can lose up to 1 kg of muscle mass from their legs in just 3-10 days whilst bedridden.
Activities of life
Leg muscles (such as quadriceps, hamstrings, and gluteal muscles) are used for major movements such as standing, walking, getting up, squatting/crouching down and running, among others. The ability to complete these activities equals to independence and quality of life for many, thus the loss of the leg strength can be a significant event.
The loss of muscle mass and strength are often observed, but less attention is paid to muscle power, the ability to produce force quickly, such as the ability to move your foot quicky at the loss of balance or walking up stairs.
It has been shown that muscle power declines earlier (around the age of 35-40) and more rapidly (with up to a 50% loss with age) than muscle mass or strength.
The loss of muscle power is significant as it relates directly to functional limitations and disability. To preserve muscle power, exercise routine must include high speed resistance training, in which you perform the lifting phase of lower limb exercises as rapidly as possible.
The specific functions of HUR products address many of the conditions mentioned above.
The power function HUR machines allow the monitoring of the power performed during training, with the target values motivating the user.
Power Function
Training view with vertical bars showing the peak power of each repetition with the target power in the form of a horizontal line behind the power bars.
The Air based resistance, Pneumatic training, mimics the human motion and allows constant resistance throughout the range of movement at all speeds. HUR’s Natural Transmission method, based on air based pneumatic technology, resistance is adapted in accordance with the production of force, regardless of the speed of the movement.
Disease prevention and treatment
Skeletal muscle is the largest organ system in our body, second to water itself. Whilst our muscles are our main movers, they also have a role as endocrine organs with many responsibilities in the management of general health.
Skeletal muscles make up almost half of the protein reserves in the human body. Proteins are the main structural components of cells with many physiological tasks such as building and repairing cells including muscle tissue and assisting in the fight against any viral and bacterial infections.
Muscles behave as our protein reserves – the “banks” we can withdraw from when our body needs to fight viruses and rebuild cells. Understanding that muscles can act as an immune organ by producing acute phase protective proteins, regular strength training is a crucial preventive action to fight against diseases.
Muscle is also the largest mass of insulin sensitive tissue in the body, and the primary site of glucose disposal, and therefore critical for the prevention and management of type 2 diabetes. Once we start to train a muscle, it has a higher capacity to store blood glucose as glycogen, thus helping to lower blood sugar levels, assisting in glucose management.
A recent study reported that men who reported no strength training had on average 2.5 times higher risk of being insulin resistant than those participants who reported moderate or high levels of strength training.
Squatting action, including the use of a HUR Leg Press -machine is a great way for training against type II diabetes and other chronic diseases as it uses multiple muscle groups at once. Training with a leg press activates many large muscle groups, such a thigh muscles (quadriceps and hamstrings) as well as the gluteal muscles. Activating these large groups enhances glycose control, but helps to build muscle, and therefore protein reserves. The HUR Leg Press is a dual cylinder equipment, allowing for bilateral training. The equipment is easily adjustable, and is easy to enter and exit, whilst providing an efficient exercise to all user groups.
Hip and knee pain
Osteoarthritis (OA) is the most common chronic condition of the joints and occurs most often in hips and knees, causing pain, stiffness, swelling, joint instability and muscle weakness. Osteoarthritis is often associated with difficulties in everyday activities such as walking, stair climbing and housekeeping.
Regular daily physical activity and appropriate exercise training are key factors in prevention, treatment and rehabilitation of OA. The effectiveness of strength training in hip and knee OA is well recognized to reduce pain, improve muscle function, prevent abnormal movement and restore normal biomechanics of hip and knee.
HUR Leg Extension/Curl -equipment is optimal for the specific training of the front (quadriceps) and back (hamstrings) muscles of the thigh. The equipment has many specific features for people suffering with joint pain. The dual cylinder equipment allows for bilateral training, allowing for leg specific training for those with one sided knee pain.
The Range of Motion (ROM) limiters allow for training in a safe range as required, eg pre-operative and post-operative rehabilitation. The starting resistance as low as 100g allows for a smooth start, and slow yet efficient progression for all. The power function allows for the monitoring and goal setting of these specific exercises. The resistance, ROM and power data collection also allow for the monitoring of post-operative recovery. The HUR Leg Extension/Curl -machine is fitted with the range of motion limiters allowing for a safe training.
Falls prevention
Approximately 30% of community-dwelling adults over 65 years of age fall each year.
One in three Australians over the age of 65 has experienced a fall in the last 12 months and 20 percent of these have needed hospitalisation.
A single fall is also a predictor of further falls as it can lead to an increased fear of falling and this in turn can alter behaviour – being less active, limiting exposure to uneven ground when walking – which leads to a greater risk of more falls.
Most falls happen during ambulation with tripping, slipping and poor balance noted as the main reasons for falls, often associated with risk factors such as muscular weakness, gait or balance disorders. Exercise interventions have been shown to significantly reduce the rate of falls.
Australian government funded two studies which both used HUR equipment in developing exercise protocols.
The first study was for community Muscling Up Against Disease (MUAD)
…and the second one was for Residential Aged Care (SUNBEAM)
Both protocols combined leg strength training with balance activities and gained great effects in the improvement of strength, but also function and confidence.
Training principles
When exercise is properly prescribed, it can work as an efficient medicine to optimise muscle health and reduce the risk of many conditions.
For improvements in strength and muscle hypertrophy: use of both multiple- and single-joint exercises with slow-to-moderate velocity, for 1–3 sets per exercise with 60–80% of 1 RM (repetition maximum) for 8–12 repetitions with 1–3 min of rest in between sets for 2–3 is recommended.
For targeting increased power in healthy older adults: perform training to improve muscular strength. perform both single-joint and multi-joint exercises for 1–3 sets per exercise using light to moderate loading (30–60% of 1 RM) for 6–10 repetitions with high repetition velocity
For enhancing muscular endurance: perform low to moderate loads for moderate to high repetitions (10–15 or more). use short rest periods for muscular endurance training, e.g., 1–2 min for high-repetition sets (15–20 repetitions or more), less than 1 minute for moderate (10–15 repetitions) sets. for circuit strength training, it is recommended that rest periods correspond to the time needed to get from one exercise station to another.
Legs truly matter, the strength in our large leg muscles are a key to an active, healthy, independent life. They allow us to get up and move, but also are our reserve banks for health, storing all the protein that we can use to build cells and fight illness.
If you are hesitant to do strength training, you can start squatting at home, but as soon as you are ready to hit the gym, always prioritise your legs, and they truly make exercise medicine!
Dr Tuire Karaharju-Huisman
Physiotherapist, Accredited Exercise Physiologist (ESSAM), PhD (Biomechanics)
Research Lead, Area Account Manager (Vic, Tas, SA)
